import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import javax.servlet.http.HttpServletResponse;
import java.net.URLEncoder;
import java.util.List;
import java.util.function.Function;
/**
 * 通用 Excel 導(dǎo)出工具類
 */
public class ExcelExportUtil {
    /**
     * 核心導(dǎo)出方法
     * @param response   HttpServletResponse
     * @param fileName   文件名
     * @param title      表格大標(biāo)題（傳空則不生成）
     * @param headers    表頭集合
     * @param dataList   數(shù)據(jù)集合 List<T>
     * @param extractors 數(shù)據(jù)提取規(guī)則集合，支持動態(tài)翻譯和格式化
     */
    public static <T> void export(HttpServletResponse response, 
                                  String fileName, 
                                  String title, 
                                  List<String> headers, 
                                  List<T> dataList, 
                                  List<Function<T, Object>> extractors) throws Exception {
        if (headers.size() != extractors.size()) {
            throw new IllegalArgumentException("表頭列數(shù)與數(shù)據(jù)提取規(guī)則數(shù)量不一致！");
        }
        // 使用 SXSSFWorkbook 防 OOM，內(nèi)存僅保留 100 行
        SXSSFWorkbook workbook = new SXSSFWorkbook(100);
        Sheet sheet = workbook.createSheet("Sheet1");
        int rowIndex = 0;
        // 1. 生成大標(biāo)題 (可選)
        if (title != null && !title.isEmpty()) {
            Row titleRow = sheet.createRow(rowIndex++);
            Cell titleCell = titleRow.createCell(0);
            titleCell.setCellValue(title);
            sheet.addMergedRegion(new CellRangeAddress(0, 0, 0, headers.size() - 1));
        }
        // 2. 生成表頭
        Row headerRow = sheet.createRow(rowIndex++);
        for (int i = 0; i < headers.size(); i++) {
            Cell cell = headerRow.createCell(i);
            cell.setCellValue(headers.get(i));
            sheet.setColumnWidth(i, 15 * 256); // 簡單統(tǒng)一列寬
        }
        // 3. 填充數(shù)據(jù)（核心亮點：使用 Function 動態(tài)取值并轉(zhuǎn)換）
        for (T data : dataList) {
            Row row = sheet.createRow(rowIndex++);
            for (int i = 0; i < extractors.size(); i++) {
                Cell cell = row.createCell(i);
                // 執(zhí)行外部傳入的 Lambda 表達式
                Object value = extractors.get(i).apply(data);
                if (value != null) {
                    if (value instanceof Number) {
                        cell.setCellValue(((Number) value).doubleValue());
                    } else {
                        cell.setCellValue(value.toString());
                    }
                } else {
                    cell.setCellValue("");
                }
            }
        }
        // 4. 寫出響應(yīng)流
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
        response.setCharacterEncoding("utf-8");
        String encodedFileName = URLEncoder.encode(fileName, "UTF-8").replaceAll("\\+", "%20");
        response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + encodedFileName + ".xlsx");
        try {
            workbook.write(response.getOutputStream());
        } finally {
            workbook.dispose(); // 清理磁盤臨時文件
            workbook.close();
        }
    }
}

@PostMapping("/exportFinanceRecord")
public void exportFinanceRecord(HttpServletResponse response, @RequestBody FinanceQuery param) throws Exception {
    List<FinanceRecord> recordList = financeRecordService.list(param);
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    // 定義表頭
    List<String> headers = Arrays.asList("記錄ID", "收支類型", "金額", "創(chuàng)建時間");

    // 定義數(shù)據(jù)提取與轉(zhuǎn)換規(guī)則（利用 Lambda 表達式）
    List<Function<FinanceRecord, Object>> extractors = Arrays.asList(
        FinanceRecord::getId, 
        record -> record.getType() == 1 ? "收入" : "支出", // 完美解決字典翻譯
        FinanceRecord::getAmount,
        record -> record.getCreateTime() != null ? sdf.format(record.getCreateTime()) : "" // 日期安全格式化
    );

    // 一行代碼調(diào)用導(dǎo)出
    ExcelExportUtil.export(response, "財務(wù)收支記錄表", "財務(wù)明細(xì)大表", headers, recordList, extractors);
}

import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.annotation.format.DateTimeFormat;
import com.alibaba.excel.annotation.write.style.ColumnWidth;
import lombok.Data;
import java.util.Date;

@Data
public class FinanceRecordExportVO {

    @ExcelProperty("記錄ID")
    @ColumnWidth(12)
    private Integer id;

    // 翻譯邏輯可以在 Service 層查詢后處理，或者實現(xiàn) EasyExcel 的 Converter
    @ExcelProperty("收支類型")
    @ColumnWidth(12)
    private String typeStr; 

    @ExcelProperty("金額")
    @ColumnWidth(15)
    private Double amount;

    @ExcelProperty("創(chuàng)建時間")
    @ColumnWidth(22)
    @DateTimeFormat("yyyy-MM-dd HH:mm:ss") // 自帶強大的格式化注解
    private Date createTime;
}

@PostMapping("/exportFinanceRecord")
public void exportFinanceRecord(HttpServletResponse response, @RequestBody FinanceQuery param) throws Exception {
    // 1. 查詢數(shù)據(jù)并轉(zhuǎn)換為 VO 集合 (推薦使用 MapStruct 等工具)
    List<FinanceRecordExportVO> voList = getAndConvertData(param);

    // 2. 設(shè)置響應(yīng)頭
    response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
    response.setCharacterEncoding("utf-8");
    String fileName = URLEncoder.encode("財務(wù)收支記錄", "UTF-8");
    response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");

    // 3. 一行代碼完成寫入！
    EasyExcel.write(response.getOutputStream(), FinanceRecordExportVO.class)
             .sheet("數(shù)據(jù)明細(xì)")
             .doWrite(voList);
}

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>easyexcel</artifactId>
    <version>3.3.4</version> </dependency>